StrPos

Function return substring position in the string.

StrPos(string, substring [, casesense [, offset]])

string	Source string.
substring	Substring for search.
casesense	Case sensitive search. 0 - case insensitive (default), 1 - case sensitive.
offset	Position in string, from search will begin. Default is 1.

Function return an integer. If substring was found, then substring position returned, counting from 1. If not found returned 0. If offset is larger then source string length, returned 0.